There are known in the prior art protective helmets which are provided with face masks having means adapted to provide an air tight seal with the wearer's face. Such helmets find use in any application in which the wearer's eyes, nose and mouth must be protected against the effect of noxious or poisonous vapors or gases.
It will readily be appreciated that an effective seal is essential if the wearer of the mask is to be afforded a good measure of protection. Various expedients have been employed in the art to cause the face seal firmly to engage the face of the wearer. For example, where the face seal is mounted on the helmet in a fixed position some adjustment may be made prior to donning the mask by adjusting the nape strap within the helmet as by a reel takeup mechanism or the like. Alternatively, the mask may be adjustably mounted on the helmet by, for example, multi-position mounting bayonet fasteners, adjustment straps, or fitting pads or a combination of these devices. While the methods of the prior art may result in the formation of an effective seal they do not provide the quick, expeditious and reliable operation which is essential in many instances, such for example as in a chemical or biological warfare situation.